Structural investigations of polymer liquid‐crystalline solutions: Aromatic polyamides, hydroxy propyl cellulose, and poly(γ‐benzyl‐L‐glutamate)

Abstract

A comparative structural investigation of the characteristics of polymer liquid‐crystalline solutions including Kevlar® (PPD‐T)/sulfuric acid, poly(Cl‐p‐phenylene terephthalamide) (Cl‐PPD‐T)/sulfuric acid, poly(γ‐benzyl‐L‐glutamate) (PγBLG)/dioxane, and hydroxypropyl cellulose (HPC)/water was undertaken. Experimental procedures included polarized light microscopy, light scattering, absorption spectra, and x‐ray diffraction on solutions at various concentrations and temperatures. Both the two‐phase region at the onset of liquid‐crystal formation and the wholly anisotropic phase were investigated. Each solution exhibited distinctive characteristics. The PPD‐T and Cl‐PPD‐T solutions were nematic, and the PγBLG and HPC solutions were cholesteric. In the two‐phase region the PPD‐T, Cl‐PPD‐T, and PγBLG (but apparently not the HPC) exhibited negatively birefringent spherulites and aggregates of spherulites. The HPC solutions only exhibited spherulitic structures in the single‐phase anisotropic system. The structures and orientations in the anisotropic phase for the various polymer solutions is considered. The helicoidal structural characteristics of the PγBLG and HPC solutions are contrasted.

Wet spinning of liquid crystalline solutions of cellulose acetate butyrate and cellulose triacetate

“…The fiber characteristics are summarized in Table 111. WAXS patterns for the CTA fibers indicated the occurrence of crystallinity; peaks are observed at spacings corresponding to 3.74 A, 4.06 A, 5.43 A, and 11.64 A. These appear to correspond to values described by Sprague, Riley, and NoetherZ1 for the Triacetate I structure.…”

Organometallic Ferrocene- and Phosphorus-Containing Polymers: Synthesis and Characterization

“…25. A thin layer of a 15% solution of polyamide 29 in dimethyl acetamide (DMAc) containing 5% LiCl showed birefringent particles on a dark field which indicates the presence of an anisotropic phase [92,93]. At higher concentrations of the polyamide and LiCl, the photomicrographs displayed domains of obvious liquid crystalline behaviour.…”

Structural Investigations of Fibers and Films of Poly(p-phenylene benzobisthiazole). Volume 1

“…[36] and Morgan [37] and an example is shown in Figure 23. It is important to reiterate that 48 hours at room temperature were required for the defect structure seen in Figures Onogi et al [38], have mistakenly termed such texture as in Figure 24 spherulites. This is a misnomer, since the supramolecular alignment of a polymer spherulite is radial and only one type of disclination has such an arrangement [34].…”